31221343 has 2 divisors, whose sum is σ = 31221344. Its totient is φ = 31221342.

The previous prime is 31221329. The next prime is 31221347. The reversal of 31221343 is 34312213.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31221343 - 2¹⁷ = 31090271 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31221343.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31221347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15610671 + 15610672.

It is an arithmetic number, because the mean of its divisors is an integer number (15610672).

Almost surely, 2^31221343 is an apocalyptic number.

31221343 is a deficient number, since it is larger than the sum of its proper divisors (1).

31221343 is an equidigital number, since it uses as much as digits as its factorization.

31221343 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 19.

The square root of 31221343 is about 5587.6061958588. The cubic root of 31221343 is about 314.8839515412.

Adding to 31221343 its reverse (34312213), we get a palindrome (65533556).

It can be divided in two parts, 3122 and 1343, that added together give a triangular number (4465 = T₉₄).

The spelling of 31221343 in words is "thirty-one million, two hundred twenty-one thousand, three hundred forty-three".